I am sorry but that is not correct.
Argumentum ad hominem literally means "argument directed at the man". Attacking the person rather than the argument itself is ALWAYS ad hominem, for validity of an assertion does not depend on the virtues of the person asserting it.
This does not change if the person has lied, deliberately misrepresented facts available to him, or was plain simple misled on what he thought was correct at the time. Like in the examples of Colin Powell and George W. Bush who either lied or were misled but were definitely proven wrong in the two examples I gave. Are you saying that you will never again listen to another word from the mouths of these two men who demonstrably gave wrong information (or "lied", as you say)?
Besides, in the article I posted, you will note that the author does not give a testimony as a unique witness (the credibility of which could be affected if we were talking about a pathological liar) but rather makes remarks on news available from other sources. Are you disputing that the British "intelligence report" that Powell praised was plagiarised, for instance? If not, then how do you justify dismissing someone's argument on the basis that he once said something which was later shown to be wrong?
Perhaps a better example of ad hominem would be the repeated referral to Bush as a "moron" and the comparison of him to Hitler by a German candidate in their recent election.
Those are insults, and any argument based on insults are of course fallacious. While I have often heard Bush being called a moron, but I don't remember it being the basis of disagreement with his policies. As in, "His foreign policy is wrong because he is a moron". I might have missed some of the more colorful arguments, but from what I can recall, the various diplomats explained how and why they disagree with Bush's policies, and then call him "moron" or "dictator" - Not as basis for arguments, or dismissing Bush's arguments, but for effect or (perhaps) personal discharge.
Example: Mandela's recent speech of end-January
"What I am condemning is that one power, with a president who has no foresight, who cannot think properly, is now wanting to plunge the world into a holocaust."
washingtonpost.com |
